The invention relates to a method of and an apparatus for producing extrusion profiles having a desired extrusion length, in particular from cast metal billets.
In the extrusion of rods, tubes, profiles, and the like of metal, such as aluminum, normally an extruded profile is produced from a billet having a certain length. The length of the extruded profile depends on the billet length extruded and on the press ratio, i.e. the ratio between the pressing pad cross section and the extrusion cross section. The extruded billet length then corresponds to the billet length minus the length or thickness of a rest to be discarded, the so-called butt thickness.
The butt retains impurities contained in on or at the billet and protects the die from overload. The butt thickness is in the order of from 3 to 5% of the billet length and forms part of the waste produced in extrusion processes.